Cheaper LED's and a look into LCD for Exposure Split from Saati Screen Toaster Thread

[Frog]

Just a suggestion mods, but how about a thread split with a realistic title for all this stuff that has little to nothing to do with Zane's project or Saati's LED unit?

I considered that from the second or so deviated post, but no one spot was completely perfect without a little confusion with a quote reference which would not then connect. Then, it just got piled on and on
I'll revisit the idea though

[ABuffington]

Image and Exposure are not the same.  The key feature that needs to be addressed is exactly how strong is the exposure on the squeegee side?  Soft? or so strong a pressure washer can't move it during development?  The image created by LCD, and even our LED systems needs to be examined.  I can hit a pure photopolymer on an MH for 5 seconds and get an image, same with LED, 3-4 will get you an image.  But if on press with HSA or Discharge, how many prints are you achieving?  I would love to have an LCD be able to hit 90k prints (The STEII is one of the few that has made it, but a lot of post exposure was needed.) 

The reality is we are exploring great new areas, but Metal Halide wasn't broken, it makes a strong exposure.  That is what any new system needs to achieve, not an image but a strong exposure.  How vertical are the side walls on the halftones?  How sharp is the ink gasket?  How many prints can you achieve with a stretch white HSA base?  Exposure is what keeps the press running.  Images on a screen can be a production screen in disguise. If it breaks down it isn't worthy of production where we make our money.  The effort put into LED is paying off, especially with CTS systems.  STEII's are quite good.  LCD will someday be a dream we have all had with the right light.  For me that is multi spectral with amplitude across the 350-410nm range and not a single spike of a wavelength.  When LED and LCD can expose a 700 micron thick film stencil with vertical side walls, sharp ink gaskets, and good exposure on the squeegee side where all the abuse takes place, then LCD will be also join LED and be a welcomed tool.  Thick stencil detail is an area that needs improvement that point MH light sources hit with ease.

This is how thick film needs to look when exposed with any light source.  700 Micron Thick Film from Murakami shot with a 5k metal halide for 10 minutes  Notice no undercutting, vertical sidewalls, super sharp ink gasket. 



This thread has a ton of great info and shows our industry is growing and experimenting, someday one of you rocket scientists will dial this in. 

Al

[Prōdigium]

Alan,

All valid points and ones that must be considered when looking at new ways to burn a screen. However I will take one exception to your comment about MH not being "broken"...its not exactly that, it is however flawed in that its not a method that provides consistency. The bulb requires extensive time to get up to power, its output is inconsistent, hence the need for a light integrator and over time the bulb loses output and lets not even get into the failure rate and costs of replacement. Its not broken, but it is deeply flawed.

LED offers instant on, stable source of UV that can be delivered in finely controlled scales. My friends LED factory here in China can test and sort LED's into batches that are all within a range of 5nm or less variance. The only thing that is not currently offered by most companies who make LED exposure units is the wattage to match the MH bulb, but not for a lack of the bulb not existing because they do. Just today I found a 1950 Watt LED chipset that I believe most certainly would burn a 700 micron cap film. Light angles would have more to do with the reflector base than the bulb itself. look at a MH bulb and it wastes 50% of its energy from having a 360 degree output, not so with a chip LED.

Its just a matter of getting the wattage up, in my opinion. Right now companies use multiple low wattage bulbs I believe because its incredibly cheap..and it works for most people, because lets be honest the percentage of printers who have ever used even thick film is low, let alone 700 micron on a 90k job. But personally, I see no technical hurdles to get get parity with MH from an LED whether its in a single light source or multiple LED's on a board. Its merely a matter of focusing the energy which can easily be controlled by design.

[Full-SpectrumSeparator]

Amazing information and definitely all factors that need to be considered and matched or improved... 

But I definitely don't see production-quality screens coming out of this at certain levels because of the resolution demand at higher qualities, not just the exposure itself -- that needs to be matched to current standards of course,  not just an "imaged" screen, but one that will hold up just as well and without a post-exposure...

But the resolution is the big issue and why this only works for spot and low-LPI halftones for the time being...  with 1080P LCD panels.

The issue is size dimensions vs. actual resolution (also the thin grids between the pixels block light and cause a weaker screen you have to get enough scatter so the pixel-grid-lines still cure but the pixels themselves which are dark don't cure, and the screen holds up to pressure wash (or is as cured as our best production-ready screens and can stand up to the ink-demands and high-volume etc)...  but the issue is with larger LCD dimensions you lose resolution.

http://teknosrc.com/resolution-vs-pixel-density-in-displays-all-you-need-to-know/

The larger area we want to expose, at the same HD quality like 1080P - ...  Pixel Density = Root((1920^2)+(1080^2))/32=68.84 ppi

for a 32" diagonal monitor, which we are getting perhaps 15" wide x 27" tall,  we are only ending up with an actual resolution of 68 DPI!      That won't do for anything but spot-colors and large halftone dots,  perhaps a low-resolution index,  but the reason I feel this is now evolving to where it is time to test further and see what is possible... is because of the cost reduction and proliferation of higher-resolution screens in the same styles where you can just disassemble and use the LCD panel.... and have it be cost-effective where 4K and 8K resolutions are at price-ranges as some of the components in a typical light-table or a more expensive DTS unit, thermal image-setter, etc.   

http://www.engadget.com/2015/10/02/jdi-8k-display/


That 8K display will get 510 pixels-per-inch.... but again that is only 17" diagonal, so 8" by 14" wont really work for most screenprint needs....   increasing the size will lower the resolution if those displays are made,  but it is clear that we have the technology, smart-phone screens are now at those 500PPi levels and  it is just we want a very large dimension area and a very high resolution.   

The market span of this industry however is where a majority of present-day printers are just one person starting up with a screen and a squeegee and some ink (you don't honestly need a press to make a screenprint,  you can just put it on something and squeegee your design... MOST present-day screenprinters are those just starting out, it is just the nature of the demographics, sure some of them won't stick with it, some will grow fast and large, others will stay at a small business or hobby level etc....     but this technology has a lot of potential down the line for the high-end and large-volume print shops for sure, just not now of course I know that...   but for the MAJORITY of printers using screens and dealing with the all-too-common issues of printing films dark enough to expose and get a "usable screen" even if you post-expose normally,  and it works for small runs and spot-color low LPI halftones... then it is still a solid step forward for the larger segment of screenprinters out there just trying to get their images to screens.    The amount of time and material and headaches reduced is easily worth the post-exposure time if it is even needed for most of these startup printers.

I just think it is more about the comparison in entry-level tech and how they are pushed to spending hundreds or more to get an inkjet printer, ink systems and RIPs, and an exposure table as well.... some of the basic entry-level exposure tables cost hundreds and it is just a box with fluorescent lights, no vacuum top etc,   so at first I see this tech actually being adopted and utilized on the startup/entry-level/beginner/small business print shops and then pushed to the higher quality/resolution/stencil-durability standards needed at the FEWER but more quality-driven printing industry shops/segment.   

Very exciting stuff,  I'm going to expose a left-chest area screen for a simple text job just using the flashlights angled so they all hit a common spot and with about an inch or two distance so they aren't just exposing only the spot-light area of each flashlight,  angling them to point at the same area and a little distance gives me a more diffused spot-light that should capture and expose the whole small left-chest area,  then I will have to obviously tape up a lot of the rest of the screen which washed out not being exposed, but it is only a test to see (with the materials I am working with) - to just make a screen that I will print a real job with... I might post-expose the screen as we do anyway, but for the majority of printers who are all startups and entry-level or just small-sized shops with the more basic equipment...  if it only takes more flashlights or buying a high-power MH or LED bulb to get a larger area to expose the same way, but even for this left-chest example  -  if I expose a screen for a REAL PRINT JOB, and I print the shirts, and all of the other quality aspects are met - the ink cures, etc... the design looks crisp and passes quality, (oh by the way if only doing left-chest size prints or smaller pad-printing etc etc then the smaller the LCD screen the higher resolution will be held, it is more for larger screenprints on shirts and textile and posters that reduces the ability for this tech to meet the resolution demands.) but anyway if I make a screen with this technique, and print a real job for a customer, and they pick it up and pay for it.... 

Then did I make a "usable" screen, or a "real" screen, and actually screenprint a "real job" through an LCD-exposed stencil??
Or is it some sort of magic and I don't understand anything about making "real" screens?   

All of the quality-standards being discussed are definite variables that need to be matched or improved... for the higher-end segment I already know its the resolutions that will matter more, they won't use it for that reason alone, not because of stencil-breakdown or other exposure issues as mentioned, but those things can be measured and will probably be easier to dial in than the resolutions which are dependent upon the LCD manufacturing and market-potentials on sizes and resolutions as that goes forward... some technology might replace LCD and then we won't have much chance besides using the tech that was put out in this era...  but I think the resolutions will at least get to the 8K level at typical consumer price-points in a few years.     Well it is all very fun and exciting and just tinkering around with the idea and trying to get to the point I can test with the higher-power full-area-coverage light,  then move to 4K panels etc.    But right now I'm gonna see if I can't at least make a "usable" screen for an actual print job.   If it is possible to make a DIY exposure table out of just a few parts like a high-power light, and an LCD monitor disassembled, and you get "usable screens" that are perhaps low-resolution and have other quality-issues, but it is still a passable quality for the startup and entry-level side of the industry, and yet it is vastly improving the process for them,  I don't see why it is not already "usable" technology for what is most likely the majority of screenprinters out there who have to deal with the whole process from art to seps to films to screens and printing.   

It might not meet the quality standards of a high-end minority... but the stuff I work on is meant to apply to all levels,  from beginners to seasoned professionals,  the LCD idea is just an experiment and a start towards making improvements and such in my own workflow and shop, and we'll see maybe it can be just a different DIY startup-level approach and people still move towards buying higher-end units and then leave the LCD behind, or they stick with it at the level they print and it works for them...  but definitely it is a massive amount of testing and work to dial in and see if the screens will reach the higher-end quality standards, I was never saying it was even usable for that yet, because the low resolutions alone make it a serious drop in quality of the image/sep itself and that is a worse factor making it unacceptable even if the screens held up to the other demands.   But the cost of testing and putting this together is LESS than a typical entry-level bulb-box exposure unit.    Instead of $400 on a bulb-box exposure unit, spend a few hundred on high-power light and $50 to $100 on LCD panel, piece of glass under it for support, etc.     

A major issue is the damage that can be done irreversibly, if people have access to laying the screens down on the panel, instead of a machine that loads the screen in and has control over how it presses the screen mesh and vacuums to the panel with the glass behind it for strength..... but if someone just drops something or a screen-frame edge hits the LCD panel it could easily CRUSH the pixels and damage the screen - another major drawback to production-quality screenmaking (at high-end,high-volume etc).    One dent in the panel and crushed the pixels the panel is useless if its in the area of exposures.   But this is all where it is larger investment into the R&D....  whereas the very cheap DIY method requires little investment and might work fine for the smaller and lower-end spot-color etc printers.     We'll see where it goes, I'll share as I discover.

[ABuffington]

So I'll give a comparison.  You start a delivery service in New York using a bike.  You out grow it with bigger packages and get a pick up.  Then outgrow it and get a van, outgrow it and get a bobtail truck.  The evolution of a printer is always towards more production, and light is one limitation of many printers.  So I get them to go with the bobtail truck from day one, which is to me a Metal Halide and I will give the STEII it's due, it is working well with our new emulsion in a 24 auto shop. 

All the drawbacks of MH are far less than breaking down every 500 shirts.  Once you buy an automatic there is no turning back to just 18 piece team orders.  You have to feed that beast.  The larger the print run, the better if you print contract.  For those selling shirt with print 200-600 is ok, but for contract work at .33-.50 you need volume and super strong screens.  Then how good is your sim process?  Recent award winning shirts are MH in most cases.  Strong pin point light equals better halftones, with better sidewalls to control dot gain. 

The less down time, the higher your profit return, the more competitive you can be.  Lose a screen on a discharge run on an automatic press and you're down 30 minutes, or 300-400 prints with labor standing around doing non paying jobs most of the time and burning the profits you just made.  Production is a race, and the length of the race grows with automatic equipment. The screens cannot fail.  They have to withstand aggressive new ink systems due to the buyers demand for PVC/Phthalate free inks.  Small shops?  a ton of em for sure and LED does work.  But back to an automatic purchase.  Printers quickly do math in their heads and see the profits piling up if they can get enough work to keep the auto running constantly.  Almost every shop starts small, this is one of the easiest industries you can grow into a million dollar business.  I cannot run production with failing screens.  Only bullet proof screens will make me money in an auto shop, only the highest quality printing penetrates the music biz or high end clothing lines. 

I go back to the thick film screens, electronics, PV, domed printing, gels, puffs, high density, glitters.  So many uses, it must be why I can't keep it in stock.  Only Metal Halide can achieve the vertical side walls and proper adhesion for long runs.  I'm sure LED or even LCD will one day replace it, it has for sure in spot color and even in typical printing, but give me a truck/Metal Halide that can handle the load when it comes to exposure.  LED is getting better and better, my 24 auto shop has proven it to me, we are in a transitional stage.  But again Metal Halide isn't broke, and regardless of drawbacks shoots the best variety of screens needed IMO.  No auto shop ever wants to say I cant' print HD, sorry.

The following images are at 65lpi (maybe higher, I never asked Tom at Motion Textile) CTS Wax, Metal halide exposure:  LED is not far away from this so while it could make a great print, can it equal this?


 

[IntegrityShirts]

All the drawbacks of MH are far less than breaking down every 500 shirts.

Cliff's Notes for this thread. For all those just joining in and not committed to reading a novel...

[Full-SpectrumSeparator]

You don't want to get me started on simulated process and separations.   

What good is all the physical equipment even if you have all of the best equipment, if your separations are a mess?      How much time, labor, materials, etc are an ever greater expense when you're printing with 12 colors a design that can print with 5 and come out even better??   

But that's another story for another day. 

[Frog]

What good is all the physical equipment even if you have all of the best equipment, if your separations are a mess?      H

But that's another story for another day.

In its own thread! LOL!

[Evo]

The following images are at 65lpi (maybe higher, I never asked Tom at Motion Textile) CTS Wax, Metal halide exposure:  LED is not far away from this so while it could make a great print, can it equal this?

That's a nice DW Collector's Series kit in a gloss natural maple finish, chrome hardware, with what looks like twin 22" kicks, a 12", 13", 16" and 18" tom set up, 5"x14" main snare and maybe a 12" accessory snare?
 
All DW 9000 series stands.

Mirrored Les Paul Standards in what looks to be tiger maple Honeyburst.


I can tell all that cause the damn detail is SO GOOD.

[Sbrem]

Yeah, I'm drooling at the quality of this print. Are you sure that's not a tobacco burst? 

Steve

[ABuffington]

A 68 tobacco burst with AAA maple top.  It's not even mine, but I get to play it all the time!  Off thread, but I'd talk music and guitars  a lot longer than screen printing. 

[BorisB]

The following images are at 65lpi (maybe higher, I never asked Tom at Motion Textile) CTS Wax, Metal halide exposure:  LED is not far away from this so while it could make a great print, can it equal this?

That's a nice DW Collector's Series kit in a gloss natural maple finish, chrome hardware, with what looks like twin 22" kicks, a 12", 13", 16" and 18" tom set up, 5"x14" main snare and maybe a 12" accessory snare?
 
All DW 9000 series stands.

Mirrored Les Paul Standards in what looks to be tiger maple Honeyburst.


I can tell all that cause the damn detail is SO GOOD.

Not to derail thread too much, just a comment. They are not using Newman Roller Frames, I beleive?

[Frog]

Not to derail thread too much, just a comment. They are not using Newman Roller Frames, I beleive?

  Derail a thread that started as a  DIY construction of an LED exposure unit, then morphed into whether led's cost too much, then to the concept of using flat panel lcd screens to expose screens in-between your favorite shows (just kidding), then an example of a print questioning whether it could be equaled using these newer exposure sources, to discussions about the musical instruments pictured in the print. And you dare now bring up the type of screens used in the print? 
Boy Boris, do you ever fit in!!

[Full-SpectrumSeparator]

Not to derail thread too much, just a comment. They are not using Newman Roller Frames, I beleive?

  Derail a thread that started as a  DIY construction of an LED exposure unit, than morphed into whether led's cost too much, then to the concept of using flat panel lcd screens to expose screens in-between your favorite shows (just kidding), then an example of a print questioning whether it coulkd be equaled using this new exposure source, to discussions about the musical instruments pictured in the print. And you dare now bring up the type of screens used in the print? 
Boy Boris, do you ever fit in!!

LOL!!     You guys don't want to hear the kind of music I make.   Speaking of derailment, I love trains.   

Bought a little 100 watt metal halide, but testing on the Digital LCD exposure I still had to put the bulb too close for a MH because of the heat.... the inverse-square-law really affects what I'm doing if comparing small UV LED flashlights at about 3 watts but held right up to the emulsion, compared to MH 100 watt bulb from a foot away.     I still had to up the timing of the exposure - getting a full-area coverage this time,  but I will explain more of the technical issues in an updated post with pictures and videos, but I need to get a better bulb and balast probably 400 watt to really test the distance/area coverage i need to get a full cure through the emulsion with MH without it being too close and causing heat issues, ... I had to push the MH test to like 20 minutes and way too close (smaller area coverage and got a little too warm) - just to get cure of the stencil but it didn't undercut the grid-lines as I WANT to happen and does happen when you get the ratio correct,  while the pixels still prevent cure...  but it held up to power-washing for few minutes, just the grid-lines left some underexposed and weak stencil...    all of these are issues I already pushed with the flashlight tests, but trying to get a larger area coverage and spend less than the high power UV LED bulbs is what I'm going for, and get an exposure in probably 5 or less minutes as a starting point.     I don't consider it a good screen unless I can get the stencil to wash out, everything else is cured and completely and holds up to power washing on both sides.    Should not need post-exposure,  post-exposing a washed out but weak screen isn't the right way to make this work.   

It is cool however that without any LCD panel and spending maybe $100 for a retail MH flood bulb/balast/fixture from home depot I can do normal exposures in 1 minute and cures much better than our fluorescent-bulb unit which takes about 4 minutes but produces weak squeegee-side exposures.    A vacuum and glass/box etc shouldn't be too hard to make,  but probably with a 400 watt MH then normal exposures get down to 30 seconds or less for typical screens, and still the LCD panel when trying that just cuts back the UV getting through by a large amount -- if you think about it, yes for 100 watts it took 1 minute to cure and get a normal exposure through the emulsion and mesh etc...  placing an LCD panel at same distance from light took over 20 minutes and not completely cured because of the panel grid lines (although I've pushed this test and gotten full cure but with the previous small-area flashlights held up close... but think about the difference in inverse-square-law with a few milimeters compared to 1 foot or more distance.)...   but the RATIO of the density or amount of UV light passing the panel in the CLEAR pixels vs. the BLACK pixels is what you're going for...   and it WORKS.   The ratio works, and even when I push the exposure longer and with higher power, as I've already tested with the UV flashlights, I can get full cure of stencil all the way through and will hold up to power washing and the DARK AREAS wash out, they dont start to cure in like maybe some are assuming happens with this method.       

I guess one simple analogy would be, imagine you have a piece of film that looks like sunglasses or tinted windows...... but your STENCIL on the film is literally black solid opaque and lets no light through.     The LCD panel is not the same, as some light will get through the black pixels as well.... but the RATIO is all you're going for,   the ratio of the "light passing" areas to the "light blocking" areas.    If the LCD panel is automatically cutting out a lot of light, then obviously when the pixels are black they cut out -that much more- light which probably equals their contrast-ratio in a way, and has anyone thought maybe the contrast ratio of LCD panels are even more than contrast-ratio of clear and ink-printed films when talking about UV light passing?    The polarizing and UV-blocking filters + the LCD on-state where the crystals are reconfigured to stop the light from passing the other polarizing filter, it is all definitely creating a similar  clear-to-dark ratio, and I'm only trying to find the right power/bulb/distance configuration to get the whole panel-area to expose and in decent times like under 5 minutes.     It really is past the tests for typical screenprint usage in low-volume, and only pushing to get to a production-level standard for the bulb power/distance/time,  then I'll make a machine I can use regularly with vacuum etc, and start pushing the quality of dot and detail and resolution I can get and probably go to 4K monitors after working out all the kinks on a low-res one.     I'll be back with some results in a few days etc,  I did a lot of testing yesterday and it is all very informative results.

[ABuffington]

Drum print was printed with Murakami Static Stretch and glues, 225/S base, 350/S colors.